Risk Scoring System to Assess Outcomes in Patients Treated with Contemporary Guideline-Adherent Optimal Therapies after Acute Myocardial Infarction

Background and Objectives: A risk prediction is needed even in the contemporary era of acute myocardial infarction (AMI). We sought to develop a risk scoring specific for patients with AMI being treated with guideline-adherent optimal therapies, including percutaneous coronary intervention and all 5 medications (aspirin, thienopyridine, ${\beta}-blocker$, angiotensin-converting enzyme inhibitor or angiotensin receptor blocker, and statin). Methods: From registries, 12,174 AMI patients were evaluated. The primary outcome was 1-year all-cause death or AMI. The Korea Working Group in Myocardial Infarction (KorMI) system was compared with the Assessment of Pexelizumab in Acute Myocardial Infarction (APEX AMI), Controlled Abciximab and Device Investigation to Lower Late Angioplasty Complications (CADILLAC), and Global Registry of Acute Coronary Events scores (GRACE) models. Results: Ten predictors were identified: left ventricular dysfunction (hazard ratio [HR], 2.3), bare-metal stent (HR, 2.0), Killip class ${\geq}II$ (HR, 1.9), renal insufficiency (HR, 1.8), previous stroke (HR, 1.6), regional wall-motion-score >20 on echocardiography (HR, 1.5), body mass index ${\leq}24kg/m^2$ (HR, 1.4), age ${\geq}70years$ (HR, 1.4), prior coronary heart disease (HR, 1.4), and diabetes (HR, 1.4). Compared with the previous models, the KorMI system had good discrimination (time-dependent C statistic, 0.759) and showed reasonable goodness-of-fit by Hosmer-Lemeshow test (p=0.84). Moreover, the continuous-net reclassification improvement varied from -27.3% to -19.1%, the integrated discrimination index varied from -2.1% to -0.9%, and the median improvement in risk score was from -1.0% to -0.4%. Conclusions: The KorMI system would be a useful tool for predicting outcomes in survivors treated with guideline-adherent optimal therapies after AMI.